Tigridia arequipensis Montesinos, Pauca & I.Revilla, 2016

Montesinos-Tubée, D. B., Pauca, A. & Revilla, I., 2016, Tigridia arequipensis (Iridaceae: Tigridieae), a new species from South Peru, Blumea 61 (1), pp. 4-7 : 4-6

Tigridia arequipensis Montesinos, Pauca & I.Revilla , sp. nov. — Fig. 1

Subgenus. Tigridia .

Etymology. Tigridia arequipensis is named after the province of Arequipa, where the species was found.

Type. Revilla 156 (holotype HSP; isotype HUSA, USM), Peru, Arequipa Region, Arequipa Province, District of Quequeña, road to Sogay , terrestrial on clayey-sandy rocky soils on rocky slopes, elev. 2676 m, S16°33'31.77" W71°26'20.40", 29 March 2011 .

Erect bulbous perennial herb 60–90 cm high, glabrous, bulb ovoid to narrowly ovoid, 2.5–3 by 1.2–2.5 cm, the outer tunics thin, pale to dark brown, densely clothed. Leaves: basal leaf linear, conduplicate, 29–62 by 3–8 mm, equal to or longer than the flowering stems, cauline leaves 1–3, rarely 4, linear, plicate, the lower 28–62 by 3–9 mm and the upper 12–30 by 1.5–7 mm; flowering stem to 82 cm high. Inflorescence a rhipidium with the bracts subequal, 3–6.5 by 4.5–6 mm, conduplicate, acute; pedicels 4–5.5 cm long, sulcate; inflorescence with 5–9 flowers in each rhipidium, erect; flowers 5–7 cm diam and 1–1.5 cm long. Tepals connivent at base forming a shallow cup, margin entire, spreading distally, basally brilliant brown, outer ones ovate, entire, acuminate, 1.9–2.3 by 7–9 mm, white to pale white (or pale lilac) with purplish maroon and dark yellow spots and stripes; inner tepals, ovate to deltoid, uniguiculate at the base, 1.9–2.2 by 8–9 mm, white to pale white or pale lilac blue with pale purplish and bluish spots and stripes, glands situated at the mid base of the inner tepals, semi-circular, brilliant. Filaments connate for c. 1.2 cm, anthers oblong, ascendent, 4–5.5 by 1–1.5 mm. Style branches 3–4 mm long, deeply bifid into 2 style arms, pale yellow to pale purple. Capsules ellipsoid, 1–2.2 by 3–5 mm, grooved and dark to pale brown. Seeds dark brown, shiny, 2 by 1 mm.

Ecology & Distribution — Tigridia arequipensis is distributed on clayey-sandy soils on rocky slopes, in the Arequipa Region in South Peru. It grows terrestrial on superficial soils on rocky slopes and occasional humid environs in xerophytic-scrubland communities at an elevation of 2490–3135 m and in association with Ambrosia artemisioides Willd. , Weberbauerocereus weberbaueri (K.Schum. ex Vaupel) Backeb. , Solanum paposanum Phil. , Anthericum eccremorrhizum Ruiz & Pav. and Mentzelia scabra subsp. chilensis (Gay) Weigend. Flowering and fruiting takes place between February and March, rarely in April. Fig. 2 shows the distributions of the Peruvian species Tigridia albicans Ravenna , T. grandiflora Salisb. , T. huyanae (J.F.Macbr.) Ravenna, T. lobata (Herb.) J.F.Macbr. , T. minuta Ravenna , T. pavonia (L.f.) DC., T. pearcei (Baker) Ravenna , T. philippiana I.M. Johnst. , T. purruchucana (Herb.) Ravenna , T. raimondii Ravenna and T. violacea Schiede ex Schltdl. ( Ravenna 1964, 1969, 1988, Brako & Zarucchi 1993, Goldblatt 1998, León 2006, Tropicos 2014).

Conservation status — Following the criteria and categories of IUCN (2012), a preliminary status of Vulnerable (VU) is assigned (A1a+D1). The new species deserves protection because its total area of occupancy is less than 200 km 2; population size is estimated to be fewer than 200 individuals (D1); and we observed a reduction of the population mainly caused by human urbanization and habitat destruction (A1a). The suitable habitats for T. arequipensis on the xeric scrubland slopes in the Socabaya, Polobaya, Mollebaya and Quequeña districts are regarded as vulnerable because changes in annual rainfall, volcanic activity, exploitation of natural resources and uncontrolled urbanization, may all potentially reduce their extent.

Additional material examined (paratypes). PERU, Arequipa Region, Arequipa Province, Montesinos 3404 (CUZ, USM), District of Socabaya, Cerro Llorón,terrestrial on clayey-sandy rocky soils on rocky slopes,elev. 2490 m, S16°29'13" W71°32'31", 8 Mar.2012; Montesinos 3495 (HSP,HUSA),District of Mollebaya, Molinoyoc, terrestrial on clayey-sandy rocky soils on rocky slopes,elev. 2820 m, S16°30'10" W71°26'44", 10 Mar.2012; Revilla 170 (HSP, USM), District of Quequeña, near Sogay, terrestrial on clayey-sandy rocky soils on rocky slopes,elev. 2749 m, S16°34'8.87" W71°24'33.47", 3Apr.2011; Revilla 188 (HSP,USM), District of Alto Selva Alegre, Parque ecológico,plain terrain with Cactaceae and shrub plants, terrestrial on clayey-sandy soils, elev. 3135 m, S16°19'31.89" W71°29'1.39", 10 Apr. 2011.

Note — The new species is morphological similar to Tigridia raimondii Ravenna and T. philippiana I.M.Johnst. but is clearly distinguished by the white to pale white (or pale lilac) outer tepals with purplish maroon and dark yellow spots and stripes, and inner tepals with pale purplish and bluish spots and stripes. Moreover. it differs by having longer basal leaves and fruits, narrower and larger bracts and longer style branches.

Figures

Fig. 1 Tigridia arequipensis Montesinos,Pauca & I.Revilla.a. Young plant in occasional humid soils near the waterfalls of Sogay,Quequeña district at 2914 m; b. mature plant in a xeric scrubland habitat, Cerro Llorón, Socabaya district at 2490 m; c. xeric scrubland habitat in Quequeña district at 2700 m; d. flower opening at Misti volcano lower slopes, Alto Selva Alegre District, 2800 m; e. flower and fruits at Sogay, Quequeña district at 2914 m; f. mature flower in Cerro Llorón, Socabaya district at 2490 m. — Photos: a, b, f, e. by D.B. Montesinos-Tubée; c, d. by I. Revilla.

Fig. 2 Map showing the distribution of Tigridia arequipensis and the other species occurring in Peru.